Studies related to uses of optical radiation for non-invasive assessment of the physiological status of biological tissues have been continued and extended. Monte-Carlo simulations were performed to establish modification of existing theory necessitated by the highly anisotropic angular scattering of biological cells and organelles. Results were used to test the limitations of diffusion theory when applied to photon transport in turbid media, and to devise "similarity transformations" for analyzing the surface intensity of transmitted or backscattered light (with R. Bonner and A. Gandjbakhche). The derived scaling relations have been confirmed with quasielastic light scattering (QELS) methodologies that have been devised to study multiple scattering in turbid colloidal suspensions (with J. Schmitt). Related studies have been undertaken to develop a theoretical basis for measuring photon transport in disordered media which contain inclusions having a fractal distribution on measurable length scales (with S. Havlin and G. H. Weiss).